<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
	<style type="text/css">
		.box{
			width: 400px;
			height: 400px;
			margin: 100px auto;
			background: skyblue;
			display: flex;
		}
		.box div{
			width: 100px;
			height: 150px;
			background: red;
			border-radius: 50px 50px 0 0;
			animation: heart 5s infinite;
		}
		.box div:nth-child(1){
			transform-origin: right bottom;
			transform: rotate(45deg);
		}
		.box div:nth-child(2){
			transform-origin: left bottom;
			transform: rotate(-45deg);
		}
		@keyframes heart{
			50%{
			width: 150px;
			height: 250px;
			background: red;
			border-radius: 75px 75px 0 0;
			}
		}
	</style>
</head>
<body>
	<div class="box">
		<div></div>
		<div></div>
	</div>
</body>
</html>